It has been awhile since a comet was visible from Earth. Twenty three years to be exact. Comet Hale-Bopp was dubbed the great comet of 1997 because of its length of time visible from the Earth was an astonishing 18 months! During this entire time, Hale-Bopp was so bright it could be seen with the naked eye.
On March 27th, 2020 another comet was discovered and named NEOWISE. NEOWISE is one of the brightest comets in a generation and stands for NASA’s Near-Earth Object Wide-field Infrared Survey Explorer mission. Observers in the Northern Hemisphere will be able to catch a glimpse of Comet NEOWISE as it zips through the inner solar system before it speeds away into the depths of space.
A majority of comets fly through the solar system invisible to humans, usually too small and dim to be seen with the naked eye. In fact, its the first time in 23 years stargazers will be able to stare up at the sky and see this bright comet with the naked eye. Eager sky watchers are turning to the heavens as Comet NEOWISE starts climbing ever higher among the evening stars.
NEOWISE will appear under the Big Dipper about 10 degrees above the horizon. If you hold out your arm, 10 degrees is roughly the part of the sky covered by your fist.
As you can see on this chart, NEOWISE will move higher in the sky and be easier to spot, reaching its apex on July 23, when it makes its closest approach to Earth. The best time to see NEOWISE is one hour after sunset in the northwest sky.
If you view NEOWISE with the naked eye, you'll see what looks like a fuzzy star with a bit of a tail. If you have binoculars or a telescope, you'll be able to see more of the comet and its dust tail. You may even be able to see the fainter blue ion tail, made from charged particles flying off the comet’s icy nucleus.
NEOWISE is visible only to observers in the Northern Hemisphere and should remain bright enough to spot through the middle of August. There will be many opportunities to catch glimpses of NEOWISE on film. A digital camera placed on a tripod and set to a five or 10 second exposure could produce an amazing image. If you'd like to use your cell phone, try framing the comet against a nice background and play with the settings on your phone. You can get great results doing this.
A comets dust tail can be 10 million miles long. The sun’s heat causes them to expel gas and dust, forming an atmospheric shell called a coma and then the pressure of solar radiation extends this structure out into a long tail which then becomes visible.
NEOWISE comes to us from the distant outer reaches of the solar system, having spent most of its life in a frigid field of icy bodies. Comets like NEOWISE are leftovers from the creation of our solar system. Comets retain the building blocks of planets in their frozen ice and can provide scientists with important information about our origins.